1. Technical Field
This invention is directed towards a system and process for selectively decoding and decompressing portions of the frames of a panoramic video.
2. Background Art
Panoramic video is constructed of a sequence of frames, each of which depicts a 360 degree view of the surrounding scene or some significant portion thereof. These frames are played in a panoramic video viewer in sequence to produce a video of the scene. A panoramic video viewer may allow a user to navigate through the scene by processing user commands to pan right, left, up or down. In other words, a person viewing the panoramic video can electronically steer his or her viewpoint around in the scene as the video is playing. Such a panoramic viewer is the subject of a co-pending application entitled “A System and Process for Viewing Panoramic Video”, which has the same inventors as this application and which is assigned to a common assignee. The co-pending application was filed on Jul. 7, 2000 and assigned Ser. No. 09/611,987, and is now U.S. Pat. No. 6,559,846. The disclosure of this patent is hereby incorporated by reference.
As can be envisioned from the above discussion of viewing a frame of a panoramic video, only a portion of the overall image is displayed to the user. Thus, much of the overall frame is not viewed at any one time. However, typically the entire panoramic video frame is input and processed by the viewer.
In general, the transmission and storage of panoramic view frames present difficulties due to the amount of information they contain. In the case where these frames are transferred to the viewer over a network, such as the Internet, they will typically be compressed in some way. Unfortunately, even in a compressed form these frames represent a considerable amount of data, and so present problems in transmitting them to the viewer, as well as processing and storing them once received. These large files are slow to be transferred to a viewer. Additionally, to process this image data in real-time requires large amounts of Random Access Memory (RAM) as well as large powerful processors. Even in a case where the frames are input to the viewer directly from a storage medium, such as a hard drive, CD, DVD, or the like, their size, especially if not compressed, imposes considerable storage and processing requirements on the viewer.